List of problems under study as of 22 February 1944 (Citroën Design Office)

In this document

This document is a list of problems under study, dated "22.2.44" at the top of page 4, listing sixteen subjects numbered 1 to 16 (points 10 to 16 being preceded by the letter "B" in the margin, page 5).

Transmission and braking

Point 1 concerns the TPV transmission shaft: "parts executed in the assembly" but "missing stabo rollers", with stress tests done and endurance tests remaining to be done p. 4.

Several sections relate to braking: the brake metering valve (point 2, "Dynamometric solution" patent requested), the hydraulic brake servo (point 3, reference to point 14), the automatic adjustment of brake lining clearance (point 4, tests "unsatisfactory" regarding feeler wear, with a question addressed to "Mr. Budin"), the variable brake gear ratio (point 5), and the trailer braking with automatic coupling (point 6).

On page 5, point B11 covers VGD hydraulic braking (dynamometric control metering valve, patent requested), point B13 the valveless brake metering valve ("patent addendum to be requested"), and point B14 a servo-braking device combined with a brake metering valve for trailer braking.

Starting and starters

Point 7 distinguishes a hydraulic starter (deemed possibly interesting "in a more industrial form for VGD" or for a tractor) and a rubber accumulation starter, whose first expansion recordings "gave satisfaction", with patent requested.

Point B12, dated in the margin "8/2/45", deals with the direct and anti-reverse starter: "landings done – satisfaction", roller freewheel study in progress, patent to be requested for the anti-reverse.

Suspension

Points 8 and 9 relate to the hydropneumatic suspension for VGD ("Study in progress") and to a differential interaction suspension for TPV, described as stemming from the VGD study and "interesting in mechanical application" for eliminating galloping springs, patent requested.

Other subjects

Point B10 concerns the synchronism indicator (automatic clutch), with the mention "patent to be taken — Miss Prot 24.2.11". Points B15 and B16 relate to cold starting: carburetor modification (fuel arrival at the choke jet) and carburetor draining/re-priming process when the engine is stopped.

At the bottom of page 5, two uncertain words ("Suspension", "Aperiodic") and almost erased lines do not allow for any reliable reading.

Context

The acronym TPV refers, in Citroën history, to the "Toute Petite Voiture" (Very Small Car) project that would lead to the 2CV, while VGD generally designates the future sedan with hydropneumatic suspension, ancestor of the DS. This period, in the middle of the Occupation (1944), corresponds to the discreet studies conducted by the Citroën design offices despite the war context.

The mention of a "Miss Prot" likely refers to a person in charge of tracking patent filings within the technical department, a common practice of the time to secure inventions.

Archivist's perspective

This document constitutes a precious dashboard of the work of Paul Magès and his team at a specific date, allowing for the measurement of the simultaneous progress of several major innovations — braking, suspension, starting — that would feed future Citroën patents.

It seems that this list was kept up to date over several months, or even more than a year, the handwritten date "8/2/45" affixed to point B12 p. 5 suggesting a review or an update after the 22 February 1944 inscribed in the header.

Point 9, relating to the differential interaction suspension for TPV, likely resonates directly with the Plans for hydropneumatic suspension with differential interaction and automatic leveling, dated a few days earlier (17 February 1944).

Likewise, point B10 on the synchronism indicator likely echoes the Plan and note on the synchronism indicator of 1943, confirming the continuity of this file over time.